Can't pack blender file for rendering on a render farm
Unfortunately, Blender does not quite pack all external files. According to the manual here:


  Not all external files can be packed
  
  Some typically heavy external files, like video ones from the Sequence
  Editor or Movie Clips, cannot be packed in a blend-file.


I would look into the render farm that you are using. Some of them may have a workaround for this issue. Looking at those video sizes though, even just uploading 1+ GB of video would take quite a while.